Tuesday, November 25, 2014

Turtles, Dinosaurs, and The New Group Archelosauria

For decades the placement of turtles in its phylogenetic tree with respect to lizards, snakes, dinosaurs, and birds has been debated. Prior methods mostly involved digging up ancient fossil turtles and looking at physical features, a fairly unaccurate and speculatory method. However, with new genomic sequencing methods, a phylogenetic tree of turtles has been put together debunking old truths, and even creating a new group in its own.

Researchers with the California Academy of Sciences along with other scientists finally tackled the turtle phylogenetic tree problem with a new sequencing method known as UCE, which stands for Ultra Conserved Elements. Using this new method, researchers were able to obtain large quantities of comprehensive genomic data and compare this to genomic data of other species. The results were astounding. Researchers debunked the notion that turtles and tortoises were more closely related to lizards and snakes than anything. Instead, researchers found that their closes relatives actually fall within birds, crocodiles, and dinosaurs. This calls for a creation of a new group, which they dubbed  Archelosauria.
Prior theorized phylogeny of turtles did not match the fossil record or archeological timelines. Now, however, with the use of the Ultra Conserved Elements techniques, the phylogeny of turtles placed within the group Archelosauria not only matches evidence found in the fossil record, but also archeological timelines. This changes the face of research for Evolutionary Biologists studying reptiles. This cutting edge technology was able to clarify a decades old problem and is a testament to how genomic sequencing techniques are improving at an exponential rate. This provides great optimism for future work in the evolution of ancient creatures.

Article Source: http://www.sciencedaily.com/releases/2014/11/141124103225.htm
Additional Source: http://www.mnn.com/earth-matters/animals/stories/turtles-more-closely-related-to-birds-than-to-lizards-according-to

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